The present disclosure relates to a seal assembly and, more particularly, to a seal assembly for a gas turbine engine exhaust duct.
Gas turbine engines, such as those which power modern military aircraft, include a compressor section to pressurize a supply of air, a combustor section to burn a hydrocarbon fuel in the presence of the pressurized air, and a turbine section to extract energy from the resultant combustion gases and generate thrust. Downstream of the turbine section, an augmentor section, or “afterburner”, is operable to selectively increase the thrust. The increase in thrust is produced when fuel is injected into the core exhaust gases downstream of the turbine section and burned with the oxygen contained therein to generate a second combustion within an exhaust duct which typically includes a convergent/divergent nozzle.
Certain engine architectures advantageously provide the ability to manipulate the exhaust duct to vector thrust and facilitate short takeoff vertical landing (STOVL) operations. Seal assemblies within such an exhaust duct need be operable in both the radial and axial directions over wide and variable temperature ranges. For a STOVL type of exhaust duct, the axial movement is typically about one third of the installed width of the seal assembly. The severe environmental conditions and the relatively large diameters have heretofore required a relatively complicated seal assembly.